Isolation of a mutant of Kluyveromyces marxianus resistant to glucose repression

Abstract

In this study, we isolated a mutant of Kluyveromyces marxianus resistance to glucose repression. To screen for depression mutants, the strains were treated with UV rays. Fifteen resistant mutant strains were isolated. The mutants were further screened for glucose-repression-resistant mutants in the presence of 2-deoxy-D-glucose, an analog to glucose and lactose as the sole carbon source. In this condition, one glucose-repression-resistant mutant was isolated. The enzyme activity in this mutant strain and the wild type strain was compared using different mediums containing 4% of each lactose and glucose and 2% glucose+2% lactose. The results demonstrated significant decreasing in glucose repression in the mutant strain as compared to the wild type. This mutant was unable to grow anaerobically on glucose in present of antimycin A, the property of rag1 mutants. This mutant is, therefore, capable of constitutive expression of β-galactosidase, which makes it suitable for industrial purposes. © 2006 Asian Network for Scientific Information.